The Roman Catholic Church has a reputation for clubbiness. (A Protestant arrives in heaven and asks St. Peter if he can visit some of his old Catholic friends. “Best if you didn’t,” Peter tells him. “They think they’re the only ones here.”) Catholics are just as prone to turn that overweening sense of orthodoxy on each other. Doctrinal hardliners never tire of telling dissenters like myself, especially those who are politicians, that we’re not “real” Catholics — many contend we should be denied communion — because our Christian as well as civic consciences have led us to support women’s ordination or legal, if limited, abortion rights.

But since Republican presidential candidate Mitt Romney tapped conservative Wisconsin Congressman Paul Ryan as his running mate last weekend, many liberal Catholics have decided it’s their turn to play the pearly gates-keeper. Ryan, a Catholic, has in the past come under fire from even the U.S. Conference of Catholic Bishops (USCCB) for his more Darwinian political ideas — especially his budget philosophy, which critics charge coddles the rich while hammering the poor and middle class — and this week more than a few progressive Catholics have doubted if not disparaged Ryan’s own Catholic bona fides. His cold-hearted betrayal of charitable Catholic social teaching, they insist, makes him unfit to call himself Christian or Catholic.

If this is where U.S. Catholics are headed between now and the Nov. 6 election, then I’ll be the first to admit that we all need to chill, hum a little Gregorian Chant and ponder our internecine differences a bit more carefully. As Los Angeles Times editorial writer Michael McGough put it this week, the anti-Ryan barrage is “the latest installment of a tiresome debate between liberal and conservative Catholics about which faction’s favored politicians are truer to the teachings of Mother Church.” How we practice our faith in the public sphere does matter. But we’ve reached a point where the battle to define what’s politically proper Catholicism, and what’s Catholically proper politics, has begun to demean the religion.

It’s not that I think Catholics shouldn’t question Ryan’s policy agenda if they feel it contradicts Christ’s call to aid the poor. Likewise, they ought to question the pro-choice position of Vice President Joe Biden, a Catholic, if they feel it contradicts their faith’s teaching on abortion. I’ve often called some of the Vatican’s doctrines and policies un-Christian and un-Catholic when they involve less than humane impulses like misogyny, homophobia or the protection of pedophile priests. Still, just as I don’t like anyone calling for my excommunication because I don’t obey Rome, I wouldn’t be so presumptuous as to assert that someone is a bad Catholic because he or she does obey Rome, because he or she defends an all-male priesthood or a ban on gay marriage. And in Ryan’s case because he believes, however disingenuous he might sound, that reducing our dangerous deficit and breaking people’s dependence on government squares with his religion’s call to alleviate poverty.

It’s one thing for me to take my feelings about Ryan’s controversial thinking into the ballot booth and pass judgment on whether or not he’s fit to govern — and yes, my interpretation of Catholicism may very well play a large role in how I vote in that regard. But it’s something else, as McGough points out, to proclaim that Ryan’s Tea Party views make him “a worse Catholic than [Catholic] politicians who favor abortion rights like Rep. Nancy Pelosi.” If anything, by taking that larger step, liberal Catholics risk sounding like Vatican hardliners.

A large part of the problem is that the Catholic vote, like the Latino and women’s vote, is considered one of the most important blocs to court in this presidential election. We represent almost a quarter of the electorate, and we’re a particularly independent-minded cohort — evidenced by polls that show a majority of U.S. Catholics disagree with the Vatican on a host of issues, including abortion. As a result, the media, especially now that Ryan is on the GOP ticket opposite Biden, are eager to sharpen the fissure between conservative and liberal Catholics. According to that cable news scenario, the two sides are supposed to pummel each other rhetorically for the next 12 weeks and let politics, in effect, decide once and for all who the “real” Catholics are.

It’s great theater, but it’s lousy theology. And I think, to his credit, even the head of the USCCB, Cardinal Timothy Dolan, has realized that by ignoring hardliner criticism and inviting President Obama, who backs abortion rights, as well as Romney to the New York archdiocese’s charitable Al Smith dinner in October.

The more immediate question, though, is whether Ryan really helps Romney with Catholics. Before he picked Ryan, Romney trailed Obama among Catholics — who went for Obama by a 54-to-45 margin in 2008 — by five points, 45% to 50%, in a recent Pew Forum on Religion and Public Life poll. Ryan, who is socially as well as fiscally right wing — he co-sponsored some of Congress’ most draconian anti-abortion bills in recent years — is certainly a boon to conservative Catholics. But they’re not who Romney needs to pick up; and Ryan, though he galvanizes the GOP base, isn’t likely to deliver many additional Catholic voters.

The Obama campaign, meanwhile, introduced its “Catholics for Obama” crew this week, led by liberal luminaries like Victoria Reggie Kennedy, widow of the late Massachusetts Senator Ted Kennedy. Their job is to convince Catholic voters that Obama isn’t the menace to religious freedom that the U.S. bishops call him, due to his administration’s mandate that church-based institutions like universities and hospitals provide birth control coverage in their health insurance. But you can bet that more of their time, energy and money will be spent persuading Catholics that Ryan is a menace to Catholic social teaching. For both sides, branding candidates as anti-Catholic might be effective politics. Just don’t call it good religion.